Hitherto, there is disclosed a device in which, when audio is reproduced, an object of adjustment operation is switched to volume of a guide sound at the time the guide sound is outputted during the adjustment operation of the reproduction volume (for example, see Japanese Patent Application Laid-Open Publication No. 2011-149852).
In the device disclosed in Japanese Patent Application Laid-Open Publication No. 2011-149852, the switching of the object of the adjustment operation is not necessarily performed at appropriate timing, and there may be cases where control different from the intention of an operator is performed.
Taking into consideration the above referred circumstances, there is a need of providing an acoustic system and a volume adjustment method in which the operation intended by an operator can be performed.